-----------------------------------------------------------------------------
-- |
-- Module      :  XMonad.Prompt.Man
-- Description :  A manual page prompt.
-- Copyright   :  (c) 2007 Valery V. Vorotyntsev
-- License     :  BSD3-style (see LICENSE)
--
-- Maintainer  :  Valery V. Vorotyntsev <valery.vv@gmail.com>
-- Portability :  non-portable (uses "manpath" and "bash")
--
-- A manual page prompt for XMonad window manager.
--
-- TODO
--
--   * narrow completions by section number, if the one is specified
--     (like @\/etc\/bash_completion@ does)
-----------------------------------------------------------------------------

module XMonad.Prompt.Man (
                          -- * Usage
                          -- $usage
                          manPrompt
                         , getCommandOutput
                         , Man
                         ) where


import XMonad
import XMonad.Prelude
import XMonad.Prompt
import XMonad.Util.Run
import XMonad.Prompt.Shell (split)

import System.Directory
import System.FilePath (dropExtensions, (</>))
import System.IO
import System.Process

import qualified Control.Exception as E

-- $usage
-- 1. In your @xmonad.hs@:
--
-- > import XMonad.Prompt
-- > import XMonad.Prompt.Man
--
-- 2. In your keybindings add something like:
--
-- >     , ((modm, xK_F1), manPrompt def)
--
-- For detailed instruction on editing the key binding see
-- <https://xmonad.org/TUTORIAL.html#customizing-xmonad the tutorial>.

data Man = Man

instance XPrompt Man where
    showXPrompt :: Man -> String
showXPrompt Man
Man = String
"Manual page: "

-- | Query for manual page to be displayed.
manPrompt :: XPConfig -> X ()
manPrompt :: XPConfig -> X ()
manPrompt XPConfig
c = do
  mans <- IO [String] -> X [String]
forall (m :: * -> *) a. MonadIO m => IO a -> m a
io IO [String]
getMans
  mkXPrompt Man c (manCompl c mans) $ runInTerm "" . (++) "man "

getMans :: IO [String]
getMans :: IO [String]
getMans = do
  paths <- do
    let getout :: String -> IO String
getout String
cmd = String -> IO String
getCommandOutput String
cmd IO String -> (SomeException -> IO String) -> IO String
forall e a. Exception e => IO a -> (e -> IO a) -> IO a
`E.catch` \E.SomeException{} -> String -> IO String
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return String
""
    -- one of these combinations should give some output
    p1 <- String -> IO String
getout String
"manpath -g 2>/dev/null"
    p2 <- getout "manpath 2>/dev/null"
    return $ intercalate ":" $ lines $ p1 ++ p2
  let sects    = [String
"man" String -> String -> String
forall a. [a] -> [a] -> [a]
++ Int -> String
forall a. Show a => a -> String
show Int
n | Int
n <- [Int
1..Int
9 :: Int]]
      dirs     = [String
d String -> String -> String
</> String
s | String
d <- Char -> String -> [String]
forall a. Eq a => a -> [a] -> [[a]]
split Char
':' String
paths, String
s <- [String]
sects]
  mans <- forM (nub dirs) $ \String
d -> do
            exists <- String -> IO Bool
doesDirectoryExist String
d
            if exists
              then map dropExtensions <$> getDirectoryContents d
              else return []
  return $ uniqSort $ concat mans

manCompl :: XPConfig -> [String] -> String -> IO [String]
manCompl :: XPConfig -> [String] -> ComplFunction
manCompl XPConfig
c [String]
mans String
s | String
s String -> String -> Bool
forall a. Eq a => a -> a -> Bool
== String
"" Bool -> Bool -> Bool
|| String -> Char
forall a. HasCallStack => [a] -> a
last String
s Char -> Char -> Bool
forall a. Eq a => a -> a -> Bool
== Char
' ' = [String] -> IO [String]
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return []
                  | Bool
otherwise                = do
  -- XXX readline instead of bash's compgen?
  f <- String -> [String]
lines (String -> [String]) -> IO String -> IO [String]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> String -> IO String
getCommandOutput (String
"bash -c 'compgen -A file " String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
s String -> String -> String
forall a. [a] -> [a] -> [a]
++ String
"'")
  mkComplFunFromList c (f ++ mans) s

-- | Run a command using shell and return its output.
--
-- XXX Merge into "XMonad.Util.Run"?
--
-- (Ask \"gurus\" whether @evaluate (length ...)@ approach is
-- better\/more idiomatic.)
getCommandOutput :: String -> IO String
getCommandOutput :: String -> IO String
getCommandOutput String
s = do
  -- we can ignore the process handle because we ignor SIGCHLD
  (pin, pout, perr, _) <- String -> IO (Handle, Handle, Handle, ProcessHandle)
runInteractiveCommand String
s
  hClose pin
  output <- hGetContents pout
  E.evaluate (length output)
  hClose perr
  return output